Abstract
Abstract. Peat growth is a frequent phenomenon in European river valleys. The presence of peat in the floodplain stratigraphy makes them hotspots of carbon storage. The long-term dynamics of alluvial peatlands are complex due to interactions between the peat and the local river network, and as a result, alluvial-peatland development in relation to both regional and local conditions is not well understood. In this study, a new modelling framework is presented to simulate long-term peatland development in river floodplains by coupling a river basin hydrology model (STREAM – Spatial Tools for River basins and Environment and Analysis of Management options) with a local peat growth model (modified version of DigiBog). The model is applied to two lowland rivers in northern Belgium, located in the European loess (Dijle (Dyle) River) and sand (Grote Nete River) belts. Parameter sensitivity analysis and scenario analysis are used to study the relative importance of internal processes and environmental conditions on peatland development. The simulation results demonstrate that the peat thickness is largely determined by the spacing and mobility of the local river channel(s) rather than by channel characteristics or peat properties. In contrast, changes in regional conditions such as climate and land cover across the upstream river basin have been shown to influence the river hydrograph but have a limited effect on peat growth. These results demonstrate that alluvial-peatland development is strongly determined by the geomorphic boundary conditions set by the river network and as such models must account for river channel dynamics to adequately simulate peatland development trajectories in valley environments.
Highlights
In many river systems throughout Europe, peat can be found in the Holocene floodplain stratigraphy (Notebaert and Verstraeten, 2010)
Active peat growth occurred mostly during the early Holocene and has disappeared at many locations due to anthropogenic land cover change since the Neolithic and its effect on the landscape sediment dynamics (Broothaerts et al, 2014b; Swinnen et al, 2020). While these have been studied as environmental archives, the dynamics of alluvial peat formation and its interaction with the local geomorphology, sediment dynamics, hydrology and human impact are not fully understood (e.g. Comas et al, 2004)
As only the local peat growth model is used, the potential differences due to processes at the basin scale or in the local river network cannot be simulated. These results show that a model setup which only simulates the internal dynamics of alluvial peatlands and that does not incorporate external factors such as seepage, river channel dynamics and river basin hydrology seems to be unable to reconstruct the observed differences in alluvial-peatland dynamics between the loess and sand belts
Summary
In many river systems throughout Europe, peat can be found in the Holocene floodplain stratigraphy (Notebaert and Verstraeten, 2010). Active peat growth occurred mostly during the early Holocene and has disappeared at many locations due to anthropogenic land cover change since the Neolithic and its effect on the landscape sediment dynamics (Broothaerts et al, 2014b; Swinnen et al, 2020). While these have been studied as environmental archives, the dynamics of alluvial peat formation and its interaction with the local geomorphology, sediment dynamics, hydrology and human impact are not fully understood A good understanding of the dynamics of alluvial peatlands in interaction with the complex nature of floodplain environments is crucial, to protect both active and buried peat and to bal-
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
